As mentioned in the related disclosure, weight material, when applied to a pipe, aids the pipe in sinking when the pipe is installed at offshore locations, under rivers, swamps, and the like. The weight material is preferably applied to the pipe with relatively uniform thickness and density. The apparatus of the present invention is particularly adapted to apply weight material which is uniform in thickness and density. For a given installation, it is often necessary to vary the total weight of material on a pipe. It is sometimes necessary to vary the density because density is often related to the compressive strength of the concrete. For instance, if it is to be exposed to rough handling, the strength which is acquired must be fairly uniform. The present invention is particularly advantageous in that the conveyor provides a substantial amount of smoothing. Smoothing is achieved internally of the slurry and on the surface. When the slurry is delivered to the apparatus, it is dumped through a housing from a mixing source typically conveyed by a conveyor, screw transfer machine, or the like, and may entrap air bubbles. The viscous nature of the slurry normally prevents escape of air bubbles. The apparatus of the present invention avoids entrapped air bubbles by placing the slurry on the conveyor belt where it is scraped as it emerges from a slot, thereby eliminating some of the bubbles. It is compressed between a compression roller and the pipe itself which compresses and removes many of the remaining air bubbles. Through this technique, the size and number of the bubbles are substantially reduced, measurably eliminating air voids in the concrete after it has been applied.
In the coating of pipe, the slurry is applied in multiple turns in helical fashion about the pipe. Adjacent turns preferably overlap somewhat. This is desirable as opposed to abutting adjacent turns and running the risk of a weakness in the coating after it has cured at the juncture of adjacent turns. The overlapped turns of coating material provide compression at the region of overlap which turns are adequately comingled to form a unitary coating as opposed to one which has a helical plane of weakness running through it.
The overlapping of adjacent turns of coating material creates a problem which is cured by the alternative embodiment to be described hereinafter. Each turn of coating material incorporates a layer of reinforcing mesh. On the exterior, a weather proofing or outer wrap is applied. The alternative embodiment to be described places the reinforcing mesh in the slurry as it is applied at an offset location. This enables adjacent turns to overlap without bending the reinforcing mesh. It is desirable that the reinforcing mesh in the cured coat of weight material form a concentric cylinder. Adjacent edges of it lap one another, but it is undesirable that the edges be folded under. The same is also true of adjacent turns of the outer or protective wrap. When a first turn is applied, it is not desirable that the next turn be placed over the wrap and folded under. This increases the likelihood of leaks in the outer wrap. The present invention accomodates this problem by aligning the outer wrap, the reinforcing mesh, and the rectangular shaped strip of coating material with offsets so that the coating material is overlapped without distorting the finished shape of the reinforcing mesh and the outer wrap.